{"gene":"RPS23","run_date":"2026-06-10T07:46:27","timeline":{"discoveries":[{"year":2014,"finding":"OGFOD1 is a prolyl hydroxylase that catalyzes the post-translational hydroxylation of Pro-62 in human RPS23 (small ribosomal protein S23). Unusually, OGFOD1 retains high affinity for and forms a stable complex with the hydroxylated RPS23 substrate. Knockdown or inactivation of OGFOD1 caused stress granule induction, translational arrest, and growth impairment, complemented by wild-type but not catalytically inactive OGFOD1.","method":"In vitro hydroxylation assay, mass spectrometry, Co-IP/stable complex characterization, siRNA knockdown with phenotypic rescue by wild-type vs. inactive OGFOD1","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"High","confidence_rationale":"Tier 1-2 / Strong — in vitro biochemical assay establishing enzymatic activity, substrate identification by MS, stable complex demonstrated, functional rescue with wild-type vs. inactive enzyme","pmids":["24550447"],"is_preprint":false},{"year":2017,"finding":"In fission yeast, Nro1 (nuclear import adaptor) binds unassembled uS12/Rps23, and Ofd1 (prolyl-3,4-dihydroxylase) dihydroxylates Rps23 Pro-62 in complex with Nro1. Concurrently, Nro1 imports Rps23 into the nucleus for assembly into 40S ribosomes. Low oxygen inhibits Ofd1 hydroxylase activity and stabilizes the Ofd1-Rps23-Nro1 complex, sequestering Ofd1 from its substrate Sre1 transcription factor, thereby freeing Sre1 to activate hypoxic gene expression. In vitro studies demonstrated direct binding of Ofd1 to Rps23, Nro1, and Sre1 through a consensus binding sequence. Rps23 expression level modulates Sre1 activity by changing the substrate pool available to Ofd1.","method":"In vitro binding assays (pulldown), dihydroxylation assay, genetic epistasis, nuclear import experiments, oxygen-dependent complex stabilization assays","journal":"eLife","confidence":"High","confidence_rationale":"Tier 1-2 / Strong — multiple orthogonal methods including in vitro reconstitution, direct binding assays, genetic epistasis, and functional oxygen-sensing mechanism in a single rigorous study","pmids":["29083304"],"is_preprint":false},{"year":2021,"finding":"A mutation in the universally conserved PNSA loop of uS12 (L48K in E. coli) causes a cold-sensitive phenotype and ribosome biogenesis defect. The L48K mutation impairs translation initiation and elongation steps. Genetic interactions with ribosome recycling factor (RRF) and peptidyl-tRNA hydrolase (Pth) reveal a novel role for the PNSA loop of uS12 in ribosome recycling.","method":"Bacterial genetics (rpsL gene mutagenesis), cold-sensitive growth phenotype, ribosome biogenesis assays, genetic interaction analysis with RRF and Pth","journal":"Molecular microbiology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — defined genetic phenotypes and epistasis with multiple factors in single lab, multiple functional assays","pmids":["33368752"],"is_preprint":false},{"year":2021,"finding":"In E. coli, mutations in uS12 (V32L or H76L) suppress growth defects caused by an unconventional initiator tRNA. H76L enhances fidelity of initiator tRNA selection, while V32L compensates for deficient fidelity through ribosome recycling factor (RRF)-dependent mechanisms. Genetic networks between uS12, IF3, initiator tRNA, EF-G, RRF, and Pth collectively govern translation fidelity.","method":"Suppressor genetics (spontaneous suppressor isolation), growth phenotype analysis, genetic epistasis with IF3, RRF, EF-G, and Pth","journal":"Molecular microbiology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic epistasis with multiple translation factors, two independent suppressor alleles characterized, single lab","pmids":["34889476"],"is_preprint":false},{"year":2025,"finding":"RsmG methylation of G527 in 16S rRNA functionally interacts with uS12: loss of m7G527 methylation (rsmG inactivation) alters streptomycin resistance phenotypes of specific uS12 mutants and, combined with uS12 R85H, generates very high streptomycin resistance. rsmG null mutations combined with specific uS12 alterations can also generate streptomycin dependence or pseudo-dependence.","method":"Bacterial genetics, MIC determination, combinatorial rsmG/uS12 double mutant analysis","journal":"Archives of microbiology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic epistasis between rsmG and multiple uS12 alleles, multiple combinatorial mutants tested, single lab","pmids":["40377667"],"is_preprint":false},{"year":1994,"finding":"The primary structure of rat ribosomal protein S23 was determined: it has 142 amino acids (N-terminal methionine is removed post-translationally), molecular weight 15,666 Da. The rat sequence is identical to human RPS23. The gene exists in 6–13 copies in the rat genome and the mRNA is ~650 nucleotides.","method":"cDNA sequencing, Southern blot hybridization","journal":"Biochemical and biophysical research communications","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct protein sequence determination from cDNA, N-terminal processing established, gene copy number by Southern blot","pmids":["8037726"],"is_preprint":false},{"year":2010,"finding":"Amphioxus RPS23 (BjRPS23) acts as a pattern recognition receptor capable of binding LPS, LTA, and PGN, and as an antimicrobial effector killing Gram-negative and Gram-positive bacteria. The core antimicrobial region was mapped to residues 67–84. BjRPS23 functions by membranolytic mechanisms including interaction with bacterial membranes via LPS/LTA/PGN, membrane depolarization, and stimulation of intracellular ROS production in bacteria.","method":"Recombinant protein production, direct bacterial killing assays, pattern recognition binding assays, truncation/deletion mapping, membrane depolarization assays, ROS measurement","journal":"Developmental and comparative immunology","confidence":"Medium","confidence_rationale":"Tier 2-3 / Moderate — multiple functional assays with recombinant protein, domain mapping, mechanistic dissection across orthogonal methods in single lab; note this is in amphioxus RPS23 (invertebrate ortholog)","pmids":["32423862"],"is_preprint":false}],"current_model":"RPS23 (uS12) is a component of the 40S small ribosomal subunit whose conserved Pro-62 is post-translationally hydroxylated by OGFOD1 (in humans) or dihydroxylated by Ofd1 (in fission yeast) in a complex involving the nuclear import adaptor Nro1; this modification and complex formation links oxygen sensing to translational regulation and hypoxic gene expression, while the conserved PNSA loop of uS12 plays roles in translation initiation, elongation, and ribosome recycling through genetic interactions with IF3, EF-G, RRF, and Pth."},"narrative":{"mechanistic_narrative":"RPS23 (uS12) is a conserved component of the 40S small ribosomal subunit whose universally conserved PNSA loop and Pro-62 residue couple ribosome function to translational fidelity and oxygen sensing [PMID:24550447, PMID:33368752]. Its conserved Pro-62 is post-translationally hydroxylated by the prolyl hydroxylase OGFOD1 in humans, which retains high affinity for and forms a stable complex with the hydroxylated substrate; loss of OGFOD1 activity triggers stress granule formation, translational arrest, and growth impairment [PMID:24550447]. In fission yeast the orthologous Ofd1 dihydroxylates Rps23 Pro-62 in a complex with the nuclear import adaptor Nro1, which both imports unassembled Rps23 into the nucleus for 40S assembly and, under low oxygen, stabilizes the Ofd1-Rps23-Nro1 complex to sequester Ofd1 away from the Sre1 transcription factor, thereby licensing hypoxic gene expression [PMID:29083304]. The conserved PNSA loop of uS12 contributes directly to translation initiation, elongation, and ribosome recycling, as revealed by bacterial mutations that confer cold sensitivity and ribosome biogenesis defects and that genetically interact with IF3, EF-G, ribosome recycling factor, and peptidyl-tRNA hydrolase [PMID:33368752, PMID:34889476]. uS12 also functionally interacts with 16S rRNA modification, since loss of RsmG-mediated m7G527 methylation modulates streptomycin resistance and dependence phenotypes of uS12 mutants [PMID:40377667].","teleology":[{"year":1994,"claim":"Establishing the primary structure of mammalian ribosomal protein S23 defined the protein product, its post-translational N-terminal processing, and confirmed sequence identity between rat and human, anchoring all subsequent functional work.","evidence":"cDNA sequencing and Southern blot in rat","pmids":["8037726"],"confidence":"Medium","gaps":["No functional or mechanistic role assigned at this stage","Gene copy number resolution (6-13 copies) leaves true expressed locus uncertain"]},{"year":2014,"claim":"Identifying OGFOD1 as a prolyl hydroxylase acting on RPS23 Pro-62 revealed that this ribosomal protein is a target of regulated post-translational hydroxylation linked to translational control, since loss of the modifying enzyme caused stress granule induction and translational arrest.","evidence":"In vitro hydroxylation assay, mass spectrometry, Co-IP, siRNA knockdown with wild-type vs catalytically inactive rescue in human cells","pmids":["24550447"],"confidence":"High","gaps":["Direct effect of Pro-62 hydroxylation on ribosome function or fidelity not resolved","Whether the stress phenotype is caused by loss of hydroxylation per se or sequestration is unclear"]},{"year":2017,"claim":"Reconstituting the Ofd1-Rps23-Nro1 complex in fission yeast showed how Rps23 hydroxylation status and abundance act as an oxygen-sensing node that controls availability of Ofd1 to the hypoxic transcription factor Sre1, connecting ribosome assembly to hypoxic gene expression.","evidence":"In vitro pulldown binding assays, dihydroxylation assay, genetic epistasis, nuclear import and oxygen-dependent complex stabilization assays","pmids":["29083304"],"confidence":"High","gaps":["Whether the human OGFOD1 system shares the Nro1/Sre1-equivalent oxygen-sensing circuit is not established here","Stoichiometry and structure of the ternary complex not resolved"]},{"year":2021,"claim":"Mutational analysis of the conserved PNSA loop of uS12 in bacteria assigned this element direct roles across translation initiation, elongation, and ribosome recycling, going beyond a purely structural ribosomal role.","evidence":"Bacterial rpsL mutagenesis, cold-sensitive growth, ribosome biogenesis assays, and genetic interaction with RRF and Pth (and IF3/EF-G in companion suppressor study)","pmids":["33368752","34889476"],"confidence":"Medium","gaps":["Molecular mechanism by which the PNSA loop affects recycling not biochemically reconstituted","Relevance of bacterial uS12 loop functions to mammalian RPS23 not tested"]},{"year":2025,"claim":"Combinatorial genetics with the 16S rRNA methyltransferase RsmG demonstrated a functional interaction between uS12 and rRNA modification, showing that m7G527 status tunes streptomycin resistance and dependence phenotypes of uS12 mutants.","evidence":"Bacterial genetics, MIC determination, rsmG/uS12 double-mutant analysis","pmids":["40377667"],"confidence":"Medium","gaps":["Mechanistic basis of the uS12-rRNA modification crosstalk not defined","Restricted to antibiotic-resistance phenotypes"]},{"year":null,"claim":"Whether the bacterial uS12 PNSA-loop functions in fidelity and recycling, and the fission yeast oxygen-sensing circuit, are mechanistically conserved in the human RPS23-OGFOD1 system remains unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No structural model of human RPS23 hydroxylation within the assembled 40S","No demonstration that human Pro-62 hydroxylation alters translational fidelity","Human equivalents of Nro1/Sre1 oxygen-sensing not characterized"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0005198","term_label":"structural molecule activity","supporting_discovery_ids":[0,2]},{"term_id":"GO:0003723","term_label":"RNA binding","supporting_discovery_ids":[2]}],"localization":[{"term_id":"GO:0005840","term_label":"ribosome","supporting_discovery_ids":[0,1]},{"term_id":"GO:0005634","term_label":"nucleus","supporting_discovery_ids":[1]}],"pathway":[{"term_id":"R-HSA-8953897","term_label":"Cellular responses to stimuli","supporting_discovery_ids":[1]}],"complexes":["40S ribosomal subunit","Ofd1-Rps23-Nro1 complex"],"partners":["OGFOD1","OFD1","NRO1"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"P62266","full_name":"Small ribosomal subunit protein uS12","aliases":["40S ribosomal protein S23"],"length_aa":143,"mass_kda":15.8,"function":"Component of the ribosome, a large ribonucleoprotein complex responsible for the synthesis of proteins in the cell (PubMed:23636399, PubMed:25901680, PubMed:25957688, PubMed:28257692). The small ribosomal subunit (SSU) binds messenger RNAs (mRNAs) and translates the encoded message by selecting cognate aminoacyl-transfer RNA (tRNA) molecules (PubMed:23636399, PubMed:25901680, PubMed:25957688). The large subunit (LSU) contains the ribosomal catalytic site termed the peptidyl transferase center (PTC), which catalyzes the formation of peptide bonds, thereby polymerizing the amino acids delivered by tRNAs into a polypeptide chain (PubMed:23636399, PubMed:25901680, PubMed:25957688). The nascent polypeptides leave the ribosome through a tunnel in the LSU and interact with protein factors that function in enzymatic processing, targeting, and the membrane insertion of nascent chains at the exit of the ribosomal tunnel (PubMed:23636399, PubMed:25901680, PubMed:25957688). Plays an important role in translational accuracy (PubMed:28257692). Part of the small subunit (SSU) processome, first precursor of the small eukaryotic ribosomal subunit. During the assembly of the SSU processome in the nucleolus, many ribosome biogenesis factors, an RNA chaperone and ribosomal proteins associate with the nascent pre-rRNA and work in concert to generate RNA folding, modifications, rearrangements and cleavage as well as targeted degradation of pre-ribosomal RNA by the RNA exosome (PubMed:34516797)","subcellular_location":"Cytoplasm, cytosol; Cytoplasm; Rough endoplasmic reticulum; Nucleus, nucleolus","url":"https://www.uniprot.org/uniprotkb/P62266/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":true,"resolved_as":"","url":"https://depmap.org/portal/gene/RPS23","classification":"Common Essential","n_dependent_lines":1207,"n_total_lines":1208,"dependency_fraction":0.9991721854304636},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[{"gene":"EIF3B","stoichiometry":10.0},{"gene":"EIF3G","stoichiometry":10.0},{"gene":"RPL19","stoichiometry":10.0},{"gene":"RPL4","stoichiometry":10.0},{"gene":"ATG7","stoichiometry":4.0},{"gene":"CAPRIN1","stoichiometry":4.0},{"gene":"EIF2S3","stoichiometry":4.0},{"gene":"EMC8","stoichiometry":4.0},{"gene":"ENY2","stoichiometry":4.0},{"gene":"METAP2","stoichiometry":4.0}],"url":"https://opencell.sf.czbiohub.org/search/RPS23","total_profiled":1310},"omim":[{"mim_id":"617412","title":"BRACHYCEPHALY, TRICHOMEGALY, AND DEVELOPMENTAL DELAY; BTDD","url":"https://www.omim.org/entry/617412"},{"mim_id":"615857","title":"2-OXOGLUTARATE- AND IRON-DEPENDENT OXYGENASE DOMAIN-CONTAINING PROTEIN 1; OGFOD1","url":"https://www.omim.org/entry/615857"},{"mim_id":"603683","title":"RIBOSOMAL PROTEIN S23; RPS23","url":"https://www.omim.org/entry/603683"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Supported","locations":[{"location":"Cytosol","reliability":"Supported"},{"location":"Endoplasmic reticulum","reliability":"Additional"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/RPS23"},"hgnc":{"alias_symbol":["S23","uS12"],"prev_symbol":[]},"alphafold":{"accession":"P62266","domains":[{"cath_id":"-","chopping":"8-32","consensus_level":"high","plddt":94.8384,"start":8,"end":32},{"cath_id":"2.40.50.140","chopping":"45-134","consensus_level":"high","plddt":96.0407,"start":45,"end":134}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/P62266","model_url":"https://alphafold.ebi.ac.uk/files/AF-P62266-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-P62266-F1-predicted_aligned_error_v6.png","plddt_mean":94.88},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=RPS23","jax_strain_url":"https://www.jax.org/strain/search?query=RPS23"},"sequence":{"accession":"P62266","fasta_url":"https://rest.uniprot.org/uniprotkb/P62266.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/P62266/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/P62266"}},"corpus_meta":[{"pmid":"372188","id":"PMC_372188","title":"Sequence of the 16 S-23 s spacer region in two ribosomal RNA operons of Escherichia coli.","date":"1979","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/372188","citation_count":109,"is_preprint":false},{"pmid":"24550447","id":"PMC_24550447","title":"OGFOD1 catalyzes prolyl hydroxylation of RPS23 and is involved in translation control and stress granule formation.","date":"2014","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/24550447","citation_count":99,"is_preprint":false},{"pmid":"947902","id":"PMC_947902","title":"The isolation of eukaryotic ribosomal proteins. 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Namibia","date":"2024-06-28","source":"bioRxiv","url":"https://doi.org/10.1101/2024.06.28.24309648","citation_count":0,"is_preprint":true}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":19657,"output_tokens":2134,"usd":0.045491,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":9132,"output_tokens":2535,"usd":0.054518,"stage2_stop_reason":"end_turn"},"total_usd":0.100009,"stage1_batch_id":"msgbatch_013LWZZT6MWaqB9qyTSeQBmU","stage2_batch_id":"msgbatch_0194ZzQaTGNpruoNJBbEMbt3","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2014,\n      \"finding\": \"OGFOD1 is a prolyl hydroxylase that catalyzes the post-translational hydroxylation of Pro-62 in human RPS23 (small ribosomal protein S23). Unusually, OGFOD1 retains high affinity for and forms a stable complex with the hydroxylated RPS23 substrate. Knockdown or inactivation of OGFOD1 caused stress granule induction, translational arrest, and growth impairment, complemented by wild-type but not catalytically inactive OGFOD1.\",\n      \"method\": \"In vitro hydroxylation assay, mass spectrometry, Co-IP/stable complex characterization, siRNA knockdown with phenotypic rescue by wild-type vs. inactive OGFOD1\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Strong — in vitro biochemical assay establishing enzymatic activity, substrate identification by MS, stable complex demonstrated, functional rescue with wild-type vs. inactive enzyme\",\n      \"pmids\": [\"24550447\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"In fission yeast, Nro1 (nuclear import adaptor) binds unassembled uS12/Rps23, and Ofd1 (prolyl-3,4-dihydroxylase) dihydroxylates Rps23 Pro-62 in complex with Nro1. Concurrently, Nro1 imports Rps23 into the nucleus for assembly into 40S ribosomes. Low oxygen inhibits Ofd1 hydroxylase activity and stabilizes the Ofd1-Rps23-Nro1 complex, sequestering Ofd1 from its substrate Sre1 transcription factor, thereby freeing Sre1 to activate hypoxic gene expression. In vitro studies demonstrated direct binding of Ofd1 to Rps23, Nro1, and Sre1 through a consensus binding sequence. Rps23 expression level modulates Sre1 activity by changing the substrate pool available to Ofd1.\",\n      \"method\": \"In vitro binding assays (pulldown), dihydroxylation assay, genetic epistasis, nuclear import experiments, oxygen-dependent complex stabilization assays\",\n      \"journal\": \"eLife\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Strong — multiple orthogonal methods including in vitro reconstitution, direct binding assays, genetic epistasis, and functional oxygen-sensing mechanism in a single rigorous study\",\n      \"pmids\": [\"29083304\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"A mutation in the universally conserved PNSA loop of uS12 (L48K in E. coli) causes a cold-sensitive phenotype and ribosome biogenesis defect. The L48K mutation impairs translation initiation and elongation steps. Genetic interactions with ribosome recycling factor (RRF) and peptidyl-tRNA hydrolase (Pth) reveal a novel role for the PNSA loop of uS12 in ribosome recycling.\",\n      \"method\": \"Bacterial genetics (rpsL gene mutagenesis), cold-sensitive growth phenotype, ribosome biogenesis assays, genetic interaction analysis with RRF and Pth\",\n      \"journal\": \"Molecular microbiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — defined genetic phenotypes and epistasis with multiple factors in single lab, multiple functional assays\",\n      \"pmids\": [\"33368752\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"In E. coli, mutations in uS12 (V32L or H76L) suppress growth defects caused by an unconventional initiator tRNA. H76L enhances fidelity of initiator tRNA selection, while V32L compensates for deficient fidelity through ribosome recycling factor (RRF)-dependent mechanisms. Genetic networks between uS12, IF3, initiator tRNA, EF-G, RRF, and Pth collectively govern translation fidelity.\",\n      \"method\": \"Suppressor genetics (spontaneous suppressor isolation), growth phenotype analysis, genetic epistasis with IF3, RRF, EF-G, and Pth\",\n      \"journal\": \"Molecular microbiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic epistasis with multiple translation factors, two independent suppressor alleles characterized, single lab\",\n      \"pmids\": [\"34889476\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"RsmG methylation of G527 in 16S rRNA functionally interacts with uS12: loss of m7G527 methylation (rsmG inactivation) alters streptomycin resistance phenotypes of specific uS12 mutants and, combined with uS12 R85H, generates very high streptomycin resistance. rsmG null mutations combined with specific uS12 alterations can also generate streptomycin dependence or pseudo-dependence.\",\n      \"method\": \"Bacterial genetics, MIC determination, combinatorial rsmG/uS12 double mutant analysis\",\n      \"journal\": \"Archives of microbiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic epistasis between rsmG and multiple uS12 alleles, multiple combinatorial mutants tested, single lab\",\n      \"pmids\": [\"40377667\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1994,\n      \"finding\": \"The primary structure of rat ribosomal protein S23 was determined: it has 142 amino acids (N-terminal methionine is removed post-translationally), molecular weight 15,666 Da. The rat sequence is identical to human RPS23. The gene exists in 6–13 copies in the rat genome and the mRNA is ~650 nucleotides.\",\n      \"method\": \"cDNA sequencing, Southern blot hybridization\",\n      \"journal\": \"Biochemical and biophysical research communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct protein sequence determination from cDNA, N-terminal processing established, gene copy number by Southern blot\",\n      \"pmids\": [\"8037726\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"Amphioxus RPS23 (BjRPS23) acts as a pattern recognition receptor capable of binding LPS, LTA, and PGN, and as an antimicrobial effector killing Gram-negative and Gram-positive bacteria. The core antimicrobial region was mapped to residues 67–84. BjRPS23 functions by membranolytic mechanisms including interaction with bacterial membranes via LPS/LTA/PGN, membrane depolarization, and stimulation of intracellular ROS production in bacteria.\",\n      \"method\": \"Recombinant protein production, direct bacterial killing assays, pattern recognition binding assays, truncation/deletion mapping, membrane depolarization assays, ROS measurement\",\n      \"journal\": \"Developmental and comparative immunology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 / Moderate — multiple functional assays with recombinant protein, domain mapping, mechanistic dissection across orthogonal methods in single lab; note this is in amphioxus RPS23 (invertebrate ortholog)\",\n      \"pmids\": [\"32423862\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"RPS23 (uS12) is a component of the 40S small ribosomal subunit whose conserved Pro-62 is post-translationally hydroxylated by OGFOD1 (in humans) or dihydroxylated by Ofd1 (in fission yeast) in a complex involving the nuclear import adaptor Nro1; this modification and complex formation links oxygen sensing to translational regulation and hypoxic gene expression, while the conserved PNSA loop of uS12 plays roles in translation initiation, elongation, and ribosome recycling through genetic interactions with IF3, EF-G, RRF, and Pth.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"RPS23 (uS12) is a conserved component of the 40S small ribosomal subunit whose universally conserved PNSA loop and Pro-62 residue couple ribosome function to translational fidelity and oxygen sensing [#0, #2]. Its conserved Pro-62 is post-translationally hydroxylated by the prolyl hydroxylase OGFOD1 in humans, which retains high affinity for and forms a stable complex with the hydroxylated substrate; loss of OGFOD1 activity triggers stress granule formation, translational arrest, and growth impairment [#0]. In fission yeast the orthologous Ofd1 dihydroxylates Rps23 Pro-62 in a complex with the nuclear import adaptor Nro1, which both imports unassembled Rps23 into the nucleus for 40S assembly and, under low oxygen, stabilizes the Ofd1-Rps23-Nro1 complex to sequester Ofd1 away from the Sre1 transcription factor, thereby licensing hypoxic gene expression [#1]. The conserved PNSA loop of uS12 contributes directly to translation initiation, elongation, and ribosome recycling, as revealed by bacterial mutations that confer cold sensitivity and ribosome biogenesis defects and that genetically interact with IF3, EF-G, ribosome recycling factor, and peptidyl-tRNA hydrolase [#2, #3]. uS12 also functionally interacts with 16S rRNA modification, since loss of RsmG-mediated m7G527 methylation modulates streptomycin resistance and dependence phenotypes of uS12 mutants [#4].\",\n  \"teleology\": [\n    {\n      \"year\": 1994,\n      \"claim\": \"Establishing the primary structure of mammalian ribosomal protein S23 defined the protein product, its post-translational N-terminal processing, and confirmed sequence identity between rat and human, anchoring all subsequent functional work.\",\n      \"evidence\": \"cDNA sequencing and Southern blot in rat\",\n      \"pmids\": [\"8037726\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"No functional or mechanistic role assigned at this stage\",\n        \"Gene copy number resolution (6-13 copies) leaves true expressed locus uncertain\"\n      ]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Identifying OGFOD1 as a prolyl hydroxylase acting on RPS23 Pro-62 revealed that this ribosomal protein is a target of regulated post-translational hydroxylation linked to translational control, since loss of the modifying enzyme caused stress granule induction and translational arrest.\",\n      \"evidence\": \"In vitro hydroxylation assay, mass spectrometry, Co-IP, siRNA knockdown with wild-type vs catalytically inactive rescue in human cells\",\n      \"pmids\": [\"24550447\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Direct effect of Pro-62 hydroxylation on ribosome function or fidelity not resolved\",\n        \"Whether the stress phenotype is caused by loss of hydroxylation per se or sequestration is unclear\"\n      ]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Reconstituting the Ofd1-Rps23-Nro1 complex in fission yeast showed how Rps23 hydroxylation status and abundance act as an oxygen-sensing node that controls availability of Ofd1 to the hypoxic transcription factor Sre1, connecting ribosome assembly to hypoxic gene expression.\",\n      \"evidence\": \"In vitro pulldown binding assays, dihydroxylation assay, genetic epistasis, nuclear import and oxygen-dependent complex stabilization assays\",\n      \"pmids\": [\"29083304\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Whether the human OGFOD1 system shares the Nro1/Sre1-equivalent oxygen-sensing circuit is not established here\",\n        \"Stoichiometry and structure of the ternary complex not resolved\"\n      ]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Mutational analysis of the conserved PNSA loop of uS12 in bacteria assigned this element direct roles across translation initiation, elongation, and ribosome recycling, going beyond a purely structural ribosomal role.\",\n      \"evidence\": \"Bacterial rpsL mutagenesis, cold-sensitive growth, ribosome biogenesis assays, and genetic interaction with RRF and Pth (and IF3/EF-G in companion suppressor study)\",\n      \"pmids\": [\"33368752\", \"34889476\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Molecular mechanism by which the PNSA loop affects recycling not biochemically reconstituted\",\n        \"Relevance of bacterial uS12 loop functions to mammalian RPS23 not tested\"\n      ]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Combinatorial genetics with the 16S rRNA methyltransferase RsmG demonstrated a functional interaction between uS12 and rRNA modification, showing that m7G527 status tunes streptomycin resistance and dependence phenotypes of uS12 mutants.\",\n      \"evidence\": \"Bacterial genetics, MIC determination, rsmG/uS12 double-mutant analysis\",\n      \"pmids\": [\"40377667\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Mechanistic basis of the uS12-rRNA modification crosstalk not defined\",\n        \"Restricted to antibiotic-resistance phenotypes\"\n      ]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"Whether the bacterial uS12 PNSA-loop functions in fidelity and recycling, and the fission yeast oxygen-sensing circuit, are mechanistically conserved in the human RPS23-OGFOD1 system remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"No structural model of human RPS23 hydroxylation within the assembled 40S\",\n        \"No demonstration that human Pro-62 hydroxylation alters translational fidelity\",\n        \"Human equivalents of Nro1/Sre1 oxygen-sensing not characterized\"\n      ]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0005198\", \"supporting_discovery_ids\": [0, 2]},\n      {\"term_id\": \"GO:0003723\", \"supporting_discovery_ids\": [2]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005840\", \"supporting_discovery_ids\": [0, 1]},\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [1]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-72766\", \"supporting_discovery_ids\": [2, 3]},\n      {\"term_id\": \"R-HSA-8953897\", \"supporting_discovery_ids\": [1]}\n    ],\n    \"complexes\": [\n      \"40S ribosomal subunit\",\n      \"Ofd1-Rps23-Nro1 complex\"\n    ],\n    \"partners\": [\n      \"OGFOD1\",\n      \"Ofd1\",\n      \"Nro1\"\n    ],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":4,"faith_total":4,"faith_pct":100.0}}